Noting that there would probably be a market among fishermen for harder-fighting fish, researchers at the University of Missouri are, as this Kansas City Star article puts it, “building fish that are lean, mean fighting machines–thanks to a little boost from creatine,” the same performance-enhancing supplement once used by Mark McGwire. It may be a while, though, before your local stream get a shot of super trout, as the federal government so far does not approve creatine in fish that are to be consumed by humans.